1. Field of the Invention
The present invention relates to a buckle apparatus for use in a seat belt for protecting an occupant in case of emergency.
2. Description of the Prior Art
In general, a buckle apparatus for use in a seat belt system is designed so that an occupant can wear an occupant arresting webbing by engagement of a tongue plate mounted at an end or an intermediate portion of the webbing with the buckle apparatus.
Some of the conventional buckle apparatuses are of a construction such that a higher load applied to a tongue plate supported in abutment on a buckle body can be reliably supported by a lock plate on opposite sides of its engaging portion with the tongue plate (see Japanese Utility Model Application Laid-open Nos. 61-55813 and 61-118406).
In the buckle apparatus of such a structure, however, if the direction of a load applied from the tongue plate to the lock plate is offset, i.e., if the direction of insertion and withdrawal of the tongue plate is offset to permit the application of a tensioning force, a component of the load is applied to the lock plate in a direction to displace the lock plate.
For this reason, the lock plate and relevant components must be fabricated firmly.